import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'dart:async';
import '../../../../core/services/auth_proxy_service.dart';
import '../../../../core/i18n/locale_utils.dart';
import '../../../../core/ui/toast_service.dart';

class UserManagementScreen extends StatefulWidget {
  const UserManagementScreen({super.key});

  @override
  State<UserManagementScreen> createState() => _UserManagementScreenState();
}

class _UserManagementScreenState extends State<UserManagementScreen>
    with SingleTickerProviderStateMixin {
  late TabController _tabController;
  bool _isAuthorized = false;
  String? _verifiedAdminPassword;
  bool _isLoading = false;

  // --- List Tab Variables ---
  List<dynamic> _users = [];
  final TextEditingController _searchController = TextEditingController();
  Timer? _debounce;

  // --- Create Tab Controllers ---
  final _formKey = GlobalKey<FormState>();
  final TextEditingController _createLoginIdController =
      TextEditingController();
  final TextEditingController _createEmailController = TextEditingController();
  final TextEditingController _createPhoneController = TextEditingController();
  final TextEditingController _createNameController = TextEditingController();

  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 2, vsync: this);
    WidgetsBinding.instance.addPostFrameCallback((_) => _verifyAccess());
  }

  @override
  void dispose() {
    _tabController.dispose();
    _searchController.dispose();
    _debounce?.cancel();
    _createLoginIdController.dispose();
    _createEmailController.dispose();
    _createPhoneController.dispose();
    _createNameController.dispose();
    super.dispose();
  }

  // --- Authentication ---
  Future<void> _verifyAccess() async {
    final passwordController = TextEditingController();

    final String? inputPassword = await showDialog<String>(
      context: context,
      barrierDismissible: false,
      builder: (context) => AlertDialog(
        title: const Text("Admin Authentication Required"),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Text("Please enter the admin password."),
            const SizedBox(height: 16),
            TextField(
              controller: passwordController,
              obscureText: true,
              decoration: const InputDecoration(
                labelText: "Password",
                border: OutlineInputBorder(),
              ),
              autofocus: true,
              onSubmitted: (value) => Navigator.pop(context, value),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, null),
            child: const Text("Cancel"),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, passwordController.text),
            child: const Text("Enter"),
          ),
        ],
      ),
    );

    if (inputPassword == null || inputPassword.isEmpty) {
      if (mounted) context.go(buildLocalizedHomePath(Uri.base));
      return;
    }

    setState(() => _isLoading = true);
    final isValid = await AuthProxyService.checkAdminAuth(inputPassword);
    setState(() => _isLoading = false);

    if (isValid) {
      if (mounted) {
        setState(() {
          _isAuthorized = true;
          _verifiedAdminPassword = inputPassword;
        });
        _loadUsers();
      }
    } else {
      if (mounted) {
        ToastService.error('Invalid Password');
        context.go(buildLocalizedHomePath(Uri.base));
      }
    }
  }

  // --- User List Logic ---
  Future<void> _loadUsers({String? query}) async {
    if (_verifiedAdminPassword == null) return;
    setState(() => _isLoading = true);
    try {
      final users = await AuthProxyService.listUsers(
        _verifiedAdminPassword!,
        query: query,
      );
      setState(() => _users = users);
    } catch (e) {
      _showError("Failed to load users: $e");
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _onSearchChanged(String query) {
    if (_debounce?.isActive ?? false) _debounce!.cancel();
    _debounce = Timer(const Duration(milliseconds: 500), () {
      _loadUsers(query: query);
    });
  }

  Future<void> _deleteUser(String loginId) async {
    if (_verifiedAdminPassword == null) return;

    final confirm = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text("Delete User"),
        content: Text(
          "Are you sure you want to delete $loginId? This cannot be undone.",
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text("Cancel"),
          ),
          FilledButton(
            style: FilledButton.styleFrom(backgroundColor: Colors.red),
            onPressed: () => Navigator.pop(context, true),
            child: const Text("Delete"),
          ),
        ],
      ),
    );

    if (confirm != true) return;

    setState(() => _isLoading = true);
    try {
      await AuthProxyService.deleteUser(_verifiedAdminPassword!, loginId);
      _showSuccess("User deleted");
      _loadUsers(query: _searchController.text);
    } catch (e) {
      _showError("Failed to delete: $e");
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  Future<void> _toggleStatus(String loginId, String currentStatus) async {
    if (_verifiedAdminPassword == null) return;
    final newStatus = (currentStatus == "enabled" || currentStatus == "active")
        ? "disabled"
        : "enabled";

    setState(() => _isLoading = true);
    try {
      await AuthProxyService.updateUserStatus(
        _verifiedAdminPassword!,
        loginId,
        newStatus,
      );
      _showSuccess("User status updated to $newStatus");
      _loadUsers(query: _searchController.text);
    } catch (e) {
      _showError("Failed to update status: $e");
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  Future<void> _editUser(Map user) async {
    if (_verifiedAdminPassword == null) return;

    final loginIDs = (user['loginIds'] as List?) ?? [];
    final loginId = loginIDs.isNotEmpty ? loginIDs.first.toString() : "";
    if (loginId.isEmpty) return;

    final nameController = TextEditingController(
      text: user['name'] ?? user['user']?['name'] ?? "",
    );
    final emailController = TextEditingController(
      text: user['user']?['email'] ?? "",
    );
    final phoneController = TextEditingController(
      text: user['user']?['phone'] ?? "",
    );

    final confirm = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text("Edit User: $loginId"),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            TextField(
              controller: nameController,
              decoration: const InputDecoration(labelText: "Name"),
            ),
            TextField(
              controller: emailController,
              decoration: const InputDecoration(labelText: "Email"),
            ),
            TextField(
              controller: phoneController,
              decoration: const InputDecoration(labelText: "Phone"),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text("Cancel"),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text("Save"),
          ),
        ],
      ),
    );

    if (confirm != true) return;

    setState(() => _isLoading = true);

    String? phone = phoneController.text.trim().isEmpty
        ? null
        : phoneController.text.trim();
    if (phone != null && !phone.contains('@')) {
      phone = phone.replaceAll(RegExp(r'[-\s]'), '');
      if (phone.startsWith('010')) {
        phone = '+82${phone.substring(1)}';
      }
    }

    try {
      await AuthProxyService.updateUserDetails(
        adminPassword: _verifiedAdminPassword!,
        loginId: loginId,
        displayName: nameController.text.trim(),
        email: emailController.text.trim(),
        phone: phone,
      );
      _showSuccess("User updated successfully");
      _loadUsers(query: _searchController.text);
    } catch (e) {
      _showError("Update failed: $e");
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  // --- Create User Logic ---
  Future<void> _createUserSubmit() async {
    if (!_formKey.currentState!.validate()) return;
    if (_verifiedAdminPassword == null) return;

    setState(() => _isLoading = true);

    String loginId = _createLoginIdController.text.trim();
    if (!loginId.contains('@')) {
      loginId = loginId.replaceAll(RegExp(r'[-\s]'), '');
      if (loginId.startsWith('010')) {
        loginId = '+82${loginId.substring(1)}';
      }
    }

    String? phone = _createPhoneController.text.trim().isEmpty
        ? null
        : _createPhoneController.text.trim();
    if (phone != null && !phone.contains('@')) {
      phone = phone.replaceAll(RegExp(r'[-\s]'), '');
      if (phone.startsWith('010')) {
        phone = '+82${phone.substring(1)}';
      }
    }

    try {
      await AuthProxyService.createUser(
        loginId: loginId,
        adminPassword: _verifiedAdminPassword!,
        email: _createEmailController.text.trim().isEmpty
            ? null
            : _createEmailController.text.trim(),
        phone: phone,
        displayName: _createNameController.text.trim().isEmpty
            ? null
            : _createNameController.text.trim(),
      );

      _showSuccess("User created successfully");
      _formKey.currentState!.reset();
      _createLoginIdController.clear();
      _createEmailController.clear();
      _createPhoneController.clear();
      _createNameController.clear();

      // Switch to list tab and reload
      _tabController.animateTo(0);
      _loadUsers();
    } catch (e) {
      _showError("Error: $e");
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  // --- UI Helpers ---
  void _showError(String msg) {
    if (!mounted) return;
    ToastService.error(msg);
  }

  void _showSuccess(String msg) {
    if (!mounted) return;
    ToastService.success(msg);
  }

  @override
  Widget build(BuildContext context) {
    if (!_isAuthorized) {
      return const Scaffold(body: Center(child: CircularProgressIndicator()));
    }

    return Scaffold(
      appBar: AppBar(
        title: const Text('User Management'),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          onPressed: () => context.go(buildLocalizedHomePath(Uri.base)),
        ),
        bottom: TabBar(
          controller: _tabController,
          tabs: const [
            Tab(icon: Icon(Icons.list), text: "User List"),
            Tab(icon: Icon(Icons.person_add), text: "Create User"),
          ],
        ),
      ),
      body: TabBarView(
        controller: _tabController,
        children: [_buildUserListTab(), _buildCreateUserTab()],
      ),
    );
  }

  Widget _buildUserListTab() {
    return Column(
      children: [
        if (_isLoading) const LinearProgressIndicator(),
        Padding(
          padding: const EdgeInsets.all(16.0),
          child: TextField(
            controller: _searchController,
            decoration: const InputDecoration(
              labelText: "Search Users",
              prefixIcon: Icon(Icons.search),
              border: OutlineInputBorder(),
              hintText: "Email, Phone, or Name",
            ),
            onChanged: _onSearchChanged,
          ),
        ),
        Expanded(
          child: _users.isEmpty
              ? const Center(child: Text("No users found."))
              : ListView.separated(
                  itemCount: _users.length,
                  separatorBuilder: (context, index) => const Divider(),
                  itemBuilder: (context, index) {
                    final user = _users[index];
                    // 일부 응답은 최상위 또는 user 하위에 필드를 포함합니다.

                    final loginIDs = (user['loginIds'] as List?) ?? [];
                    final loginId = loginIDs.isNotEmpty
                        ? loginIDs.first.toString()
                        : "Unknown ID";
                    final name =
                        user['name'] ?? user['user']?['name'] ?? "No Name";
                    final status = user['status'] ?? "unknown";
                    final isEnabled = status == "enabled" || status == "active";

                    return ListTile(
                      leading: CircleAvatar(
                        backgroundColor: isEnabled
                            ? Colors.green.shade100
                            : Colors.grey.shade300,
                        child: Icon(
                          Icons.person,
                          color: isEnabled ? Colors.green : Colors.grey,
                        ),
                      ),
                      title: Text(name),
                      subtitle: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            loginId,
                            style: const TextStyle(fontWeight: FontWeight.bold),
                          ),
                          Text(
                            "Status: $status",
                            style: TextStyle(
                              color: isEnabled ? Colors.green : Colors.red,
                              fontSize: 12,
                            ),
                          ),
                        ],
                      ),
                      trailing: Row(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          IconButton(
                            icon: const Icon(Icons.edit, color: Colors.blue),
                            tooltip: "Edit User",
                            onPressed: () => _editUser(user),
                          ),
                          IconButton(
                            icon: Icon(
                              isEnabled ? Icons.block : Icons.check_circle,
                              color: isEnabled ? Colors.orange : Colors.green,
                            ),
                            tooltip: isEnabled ? "Disable User" : "Enable User",
                            onPressed: () => _toggleStatus(loginId, status),
                          ),
                          IconButton(
                            icon: const Icon(Icons.delete, color: Colors.red),
                            tooltip: "Delete User",
                            onPressed: () => _deleteUser(loginId),
                          ),
                        ],
                      ),
                    );
                  },
                ),
        ),
      ],
    );
  }

  Widget _buildCreateUserTab() {
    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Center(
        child: Container(
          constraints: const BoxConstraints(maxWidth: 600),
          child: Form(
            key: _formKey,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                if (_isLoading) const LinearProgressIndicator(),
                const SizedBox(height: 20),
                TextFormField(
                  controller: _createLoginIdController,
                  decoration: const InputDecoration(
                    labelText: "Login ID (Required)",
                    border: OutlineInputBorder(),
                    helperText: "Unique identifier (Email or Phone)",
                  ),
                  validator: (value) => value == null || value.isEmpty
                      ? 'Please enter Login ID'
                      : null,
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _createNameController,
                  decoration: const InputDecoration(
                    labelText: "Display Name",
                    border: OutlineInputBorder(),
                    prefixIcon: Icon(Icons.person),
                  ),
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _createEmailController,
                  decoration: const InputDecoration(
                    labelText: "Email",
                    border: OutlineInputBorder(),
                    prefixIcon: Icon(Icons.email),
                  ),
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _createPhoneController,
                  decoration: const InputDecoration(
                    labelText: "Phone Number",
                    border: OutlineInputBorder(),
                    prefixIcon: Icon(Icons.phone),
                    helperText: "010-xxxx-xxxx",
                  ),
                ),
                const SizedBox(height: 32),
                FilledButton(
                  onPressed: _isLoading ? null : _createUserSubmit,
                  style: FilledButton.styleFrom(
                    padding: const EdgeInsets.symmetric(vertical: 16),
                  ),
                  child: const Text("Create User"),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}